The folks at attrition.org have been stalwarts in providing information to the security community for ages, it seems. I first discovered them via their defacement mirror, which they ceased maintaining long ago because site defacements became so common there was no point. About three years ago they began actively tracking data loss reports. Earlier this year they started to do a sign-off like they did with the defacement mirror, but the response from the community was so overwhelmingly positive towards the contribution attrition.org had made, they decided to keep it going.

If you've not checked out the mailing list, and you have anything to do with data security, you may want to. In addition to maintaining a mailing list, they also maintain an open source database of data loss incidents. It's a .CSV file, meaning it's easy to work with. When you look at who has been hit and the numbers, it's not pretty, but it is good information to know. It puts in perspective that anyone can be hit and therefore none of us should be complacent.